This is a somewhat-annoying issue... In C3D 2010 or 2011, I could do "Re-import" on the Survey Import Event, and it would work. In C3D 2012 and 2013, it fails to delete the Survey Points, and pops up the "Duplicate point number resolution" dialog box. If I've deleted any points in my source file, those points still exist after the "Re-import" command completes, which is an error.
I haven't used 2012 or 2013 yet, but I have seen this behavior on occaision. It doesn't seem to follow any pattern that I can tell. When I encounter it I right-click on the event, click remove from drawing, and then re-import.